Rat-holing and poor flow show up when discharge continues through a narrow channel while the wall retains product. Repeated quantity and level comparisons are more useful than a single photograph or isolated alarm.
Do not enter the vessel or work beneath the outlet to confirm what remains. Keep the area controlled until the material position and approval route have been reviewed.
The draw-down pattern helps separate a wall-retention problem from an outlet or feeder fault.
Some flow can continue while usable capacity falls
During rat-holing, a narrow channel may keep feeding product while material stands against the wall. Compare dispatched quantities with the level trend to see that gradual loss. A silent feeder and unchanged level indicate a different restriction and should be reported separately.
For powder build-up, see powder silo cleaning. A local restriction may need silo blockage removal. The article on why silo material stops flowing sets out the distinctions in plain language.
What operator record helps identify rat-holing. Level trends, discharge quantities and observations of a narrow central draw-down can show that material remains against the wall while some flow continues.
Poor flow can leave unstable material. Do not enter, probe or stand beneath the load without authorised controls and a safe system of work.